1. Field of the Invention
This invention relates to spray cooling systems for cooling large volumes of heated water.
2. Description of the Prior Art
The pressure on industry to avoid thermal pollution by the discharge of heated plant water to river, lake or ocean has drastically increased the demand for efficient, large capacity water cooling systems. Such systems, for example, may be required to cool from 400,000 to 1,000,000 or more gallons per minute of heated water discharged from the cooling systems of power plants sufficiently to enable its discharge without damage to the ecology or its recycling to the plant cooling system. Typical spray cooling systems pump the heated water from a channel, in which it flows for discharge or recycling to nozzles mounted on fixed structures or floats, which spray it back to the channel. Many such nozzles are needed, of large capacity of 500 to several thousand gallons per minute or more.
Such spray cooling systems as heretofore provided have had certain deficiencies which have led to a general dissatisfaction with this type of system for the purpose. One major deficiency has been too low a cooling efficiency in relation to capital and power costs. Another such deficiency has been the development of excessive mist which, under wind-drift conditions, can become a public nuisance, and is also a loss to the cooling system, reducing cooling efficiency. It has been ascertained that a primary cause of these deficiencies has been the failure of the prior art to provide suitable spray forming equipment in such systems.
In particular, the spray nozzles in general use for the purpose are of a type that generates a conical spray surrounding the nozzle which expands outwardly as it rises and then falls more or less vertically into the receiver. Since the nozzle is located close to the surface, the sheet-like spray forms a double curtain wall surrounding the nozzle which effectively blocks access of fresh, unsaturated air to the undersurface of the spray, that is, the inside surface of the curtain walls of spray, and, to a somewhat lesser extent, to the inner upper surface of the spray. Thus, effective cooling of the sprayed water by convection to and evaporation into the air is largely confined to the outer surface of the spray. In addition, existent designs of such nozzles tend to form a far from uniform spray, with a substantial proportion of oversize drops (1 inch or more in diameter). Further, such nozzles can be used only where surrounded by the receiver, and are not suitable for mounting on land at the side of the receiver, as may be desirable.